1. Field of the Invention
The present invention relates to a color cathode ray tube (CRT), and more particularly, to a tension mask frame assembly having an improved thermal compensation feature for compensating for “mislanding of an electron beam” (i.e., electrons that hit the mask and heat the mask as opposed to electrons that go through a slit in the mask to excite a flourescent film) due to thermal deformation of a mask receiving tension and a frame supporting the mask, and a color CRT using the same.
2. Description of the Related Art
In a typical color CRT, three electron beams are emitted from an electron gun, pass through electron beam passing holes of a mask having a color selection function, and then land on red, green, and blue fluorescent substances of a fluorescent film formed on a screen surface of a panel and excite the fluorescent substances, to form an image.
In the color CRT forming an image, the mask having a color selection function is divided into a dot mask adopted in a monitor of a computer and a slot (or a slit mask) mask used in a television. In a tension mask, one of the slot masks, considering a flat screen surface, tension is applied to the frame to compensate for distortion of an image and widen a view angle of a screen.
In such a scenario, not all of the electron beams go through the slots. Some of the electron beams impinge in the tension mask instead of going through to the flourescent film. These electron beams then heat the tension mask and the frame. If the design of the tension mask does not compensate for temperature changes, these electron beams that land on the tension mask will heat up the tension mask and the frame causing the mask and the frame to move. If these movements are not properly compensated for in the design of the frame, the slots will move thereby causing even a larger percentage of the electron beams to hit the mask instead of going through the slots resulting in a poorer image quality on the color CRT display.
What is needed is a design for a frame of a tension mask that properly compensates for all movements of the tension mask so that the quality of the image does not deteriorate with use.